A well packer provides a seal in an annulus formed between an exterior surface of a tubular and an interior surface of well casing or a wellbore. Known forms of well packers are introduced to the downhole environment in which they are to be used in an unexpanded condition and expanded in-situ to provide the desired seal. In one form, the well packer expands upon coming into contact with a well fluid. In another form, the well packer comprises movable parts that are actuated in-situ to form the seal. The present inventor has appreciated that conventional packers have shortcomings and the present invention has been devised in the light of this appreciation.